Chinese herb-resistance and adherence to human uroepithelial cells of uropathogenic Escherichia Coli

Background: In order to define the virulence factors between Chinese herb-resistant uropathogenic E. coli and susceptible strains, the UPEC isolates were classified into two groups according to its resistance to Chinese herbs.Materials and Methods: The susceptibility profile of strains was determined by disk diffusion method. PCR systems were used to detect genes encoding papC, Aer, hly and cnf1. Isolated human urothelial cells were incubated in vitro and investigated with light microscope immunohistochemistry. Adhesion of E. coli to urothelial cells was studied in vitro.Results: The results showed that, among the 105 UPEC isolates, 18 were resistant to the herbal concoction. Cnf1 and papC occurred in ≥66.7%, of herb-resistant isolates, while, hly and Aer occurred in 22.2% and 27.8% of strains respectively. Only one gene (Cnf1) occurred in >40%, of Herb-susceptible isolates. Other genes were also found in susceptible isolates: papC (20.7%), hly (11.5%), and Aer (6.9%). Light microscopy  and immunochemical investigations demonstrated the normal pelvic transitional epithelial cells cultured. The adherence of strains in both groups increased in 30 min., and reached its peak at 60, (Susceptible E. coli) or 120 min., (Resistant E. coli). The adhesion of the susceptible bacteria to human uroepithelial cells was significantly lower compared with that of the resistant E. coli (p<0.05).Conclusion: These findings revealed that, Chinese herb-resistant uropathogenic E. coli isolates that are hemolytic, and have Aer, papC, hly, Cnf1 genes are more able to be uropathogenic and adherent.Key words: Escherichia coli; Adherence; Virulence genes; Human uroepithelial cells; Chinese herb-resistance

The observation of a positive magnetoresistance and close correlation among lattice, spin and charge around TC in antipervoskite SnCMn3

The temperature dependences of magnetization, electrical transport, and thermal transport properties of antiperovskite compound SnCMn3 have been investigated systematically. A positive magnetoresistance (~11%) is observed around the ferrimagnetic-paramagnetic transition (TC ~ 280 K) in the field of 50 kOe, which can be attributed to the field-induced magnetic phase transition. The abnormalities of resistivity, Seebeck coefficient, normal Hall effect and thermal conductivity near TC are suggested to be associated with an abrupt reconstruction of electronic structure. Further, our results indicate an essential interaction among lattice, spin and charge degrees of freedom around TC. Such an interaction among various degrees of freedom associated with sudden phase transition is suggested to be characteristic of Mn-based antiperovskite compounds.Comment: 13 pages, 5 figure

Comparison of chemical profiles and effectiveness between Erxian decoction and mixtures of decoctions of its individual herbs : a novel approach for identification of the standard chemicals

Acknowledgements This study was partially supported by grants from the Seed Funding Programme for Basic Research (Project Number 201211159146 and 201411159213), the University of Hong Kong. We thank Mr Keith Wong and Ms Cindy Lee for their technical assistances.Peer reviewedPublisher PD

Near tip strain evolution under cyclic loading

The concept of ratchetting strain as a crack driving force in controlling crack growth has previouslybeen explored at Portsmouth using numerical approaches for nickel-based superalloys. In this paper, we reportthe first experimental observations of the near-tip strain evolution as captured by the Digital Image Correlation(DIC) technique on a compact tension specimen of stainless steel 316L. The evolution of the near-tip strainswith loading cycles was studied whilst the crack tip was maintained stationary. The strains were monitored overthe selected distances from the crack tip for a given number of cycles under an incremental loading regime. Theresults show that strain ratchetting does occur with load cycling, and is particularly evident close to the crack tipand under higher loads. A finite element model has been developed to simulate the experiments and thesimulation results are compared with the DIC measurements